Electrical cableway system.



Patented Dec. 14, 1909.

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0. ADAM.. ELECTRICAL CABLEWAY SYSTEM.

APPLXGTION FILED APB.20, 1908.

OTTO ADAM, 0F DRESDEN, GERMANY.

ELECTRICAL OABLEWAY SYSTEM.

Specicatlon of Letters Patent.

Patented Dec. 14, 1909.

Application letl April 20, 190B. Berlll No. 428,035.

To all whom it may concern:

Be it known that I, O'r'ro ADAM, chief engineer, a subject of the German Emperor, residiu at Uhlandstrasse 37, Dresden, (ingdom o Saxony@ Germany, have invented new and useful improvements in Electrical Cableway Systems, of which the following is a specification.

The invention relates to improvements in the ty of electrically actuated cable sys tems i ustrated in my former atent No. 820,464, dated March 15z 1906. the cable system illustrated in said patent there was em loyed a series or compound motor for maintaining the normal tension on thetraw cling cable, and as is well known such a motor increases its speed upon a decrease of load. When the apparatus was employed between two shi s for loading coal at sea. the travelilw cable and tensioning or straining rope bolli became slack as the vessels a proached each other. This slacking of t e travelingl cable rmitted the part of the motor (t e field ame) operating the straining rope to begin its rotation to wind up the straining rope. As this rotation of the field frame increased the relative number of rotations per unit of time of the armature with res ect to the field, while the actual speed o the armature remained substantiall constant, the counter E. M. F. develope b the motor increased, and the current o the motor and therefore the torque decreased, conse uently, the motor did not respond as quick y in winding nip the straining rope to restore the norma tension on the traveling cable as would have been the case had the torque of the motor been maintained constant, under the relatively increased s eed of the armature with respect to the fie d.

Inasmuch as vessels in a heavy sea way approach each other very quickly and at rapidly recurring intervals, due io thc wave action, it is necessary to maintain the proper tension on the traveling cable that thc motor part actuating the straining rope of the cale responds quickly to wind up the straining rope. In the patent. aforesaid the rcsponsivc action of t 1c motor in restoring the tension of the cubic was not quick enough and it is an essential purpose of tho present invention to correct. this dilliculty.

In tho accompanying drawings: Figure 1 is n. diagrammatic view of-u cubic system involving tho invention, Figs. 2 and 3 show modified forms of connecting the operating motor and the regulating dynamo electricmachine.

Referring to the drawings it will be noted that the two vessels are connected b a suitable tow-rope, and between the vesse s passes the endless traveling cable d assing over suitable guide sheaves on eac vessel and around a pulley or driving drum operated by a rotating field frame g of the motor A. A tension or straining Arope e is connected at one end to a pulle e' engagin the up r reach of cable d an is connect at its ot er end to a windin drum or pulley operatively connected with t e amature f of said motor. Connected with the armature f of the motor, by a chain or belt drive b, is a small generator, or d namo electric machine B. As soon as the s acking of the cable d causes the amature f to revolve to -wind up tension rope e, the armature of the dynamo is rotated with a speed pro ortional to the rotation of the armature i) and develops a current that is directly pro ortional to the relative increase in the number of rotations of the motor A due to the rotation of the armature f. The current from the dynamo B is conducted through a oountencompound winding of the motor A and thereby effects n weakening of the motor field to a degree corresponding to the increase in the relative speed of the motor. This causes a. corre sponding increase in the current flowing in the motor armature f which produces a quicker response in the increase of the speed of the armature and therefore a practically instantaneous tightening of the winding or straining rope c, which restores the normal tension on cable d.

As is well known the counter E. M. F. of an electric motor is directl proportional to the speed of rotation ot tie armature and the siren h of the field` or the number of lines of Grec cut per unit of time, and that the higher the counter E. M. l". thc less thc cul-rent [lowing in the armature and the less the torque of the motor. By weakening the field the counter E. M. F. is reduced and the armature current and the torque incl-mises, so that. with n given load the armature speed increases until thc counter E. lll. I". again reaches its normal. Il. will ho secu therefore that the ultimato cll'ect of the counter current from dyunuio il is to increase thu upcnd and power of thc motor nrnulturc f in suhstuntirlly tho suino proportion that tho rotu- Utl llo

2 rnaanoo tion of the normally stationary field frame increases the counter E. M. F. of the motor, and by careful adjustment of the current dclivered to the motor A from the dynamo an 5 exact compensation may be efectedso that the portion of the motor operating the strainin rope will respond instantly and effective y to restore the tension on cable d. Conversely when the magnetic field of the motor is increased, the counter E. M. F. is

increased and the current through the armature decreases, hence the speed of the armature decreases until the counter E. M. F. again becomes normal. Therefore when the tension on cable d becomes excessive, due to the vessels separating and the straining rope drives the armature f in unwinding, the current delivered b compensatingithe dynamo B increases the eld of motor decreasing the torque of the amature and relieving the excessive strain on the cable until the armature ceases its movement and normal tension of cable d is restored.

For the ur ose of this invention it is immaterial w et er the motor A is a seriesz a shunt or a compound motor, and likewise the general e'ect is the saine whether the energy of the compensating dynamo acts throu b a special winding on the motor or direciy u on the energizin winding of said motor an it will be un erstood that the ecial case referred to in connection with ig. 1 is merely illustrative of one mode of applying the invention. The essential feature ofthe invention is that the auxiliary dynamo B furnishes a compensating current only during tlie operation of the part of the motor which intermittently operates the straining rope e to maintain a. substantially uniform tension on cable d.

Instead of the foregoing connection between the dynamo B and the motor A, the arrangements illustrated in Figs. and 3 may be employed. As shown in Fig. 2 the armature c of the auxiliary dynamo is driven by the continuously rotating lield frame g of the motor and is connected iii a shunt to the series field winding S of the motor. The field s of the auxiliary dynamo is iii series with the motor field S. Willi the field frame rotating to drive. the traveling cable under nornial strain or tension, the armature c produc-cs a counter E. M. I". cfg so that only a slight current passes through said armature e and shunt W. When the traveling cable lic-comes slack und the motor urinaturc A begins to wind up the tension ro ie,

the motor current declines owing to thc iiicrcased counter E. M. I". developed by the inotor. As the cui-rent. in series-winding S of the motor und s of the auxiliary dynamo decreases, the count-cr ll. M. 14'. of the dynaino armature c also decreases, und the eiii'- rent passing through shunt W und through "5 the inotoi al'nnitui'e A increases, so that the toriuc 0f the motor is maintained substantial y constant und armature A quickly rcsponds to wind up the tension rope and restore the tension on the traveling cable, after which the systeiii resumes its normal operation with the armature A stationary. Dui'- ng the rotation of thc armature A should there occur mi increase in tlic speed of rotating field frame g diie to the decreased load, an additional compensating winding n may be employed, said winding being energized from armature c and operating in opposition to tlie field windinlf s of the anxiliary dynamo to neutralize the relative iiicrease in the tension developed by armature c in consequence of its increased speed. When the load on the motor increases duc to an increase in the tension of the traveling cable, the armature A rotates in the opposite direction and the current thi-ou h the motor is increased with a correspon ing increase iii the strength of field s of the dynamo. The tension of the dynamo armature c in creases accordingly and sends current through the shunt W and field S of the motor thereby increasing the strength of the motor field and reducing the relative speed of rotation of the motor parts.

In the modification shown in Fig. 3, the armature cof the regulating dynamo is driven b the rotating armature A of the motor w ich operates the strainin rope e and said armature c is connecte in the shunt field winding n of the motor. The field N of the dynamo ma be energized from any suitable source. iile the armature A of the motor is at rest the armature c is also stationary and produces no current. lVlien, however, armature A rotates to wind up straining rope e, armature c of the dynamo produces an clecti'o-riiotive force in opposition to that in tlie main iiiotor circuit and weakens the current in the shunt field winding N resulting in an increase in the speed of armature A and a more rapid winding of the tension rope c. When the tension of the armature c rises above that of tlie motor mains the current in sliiint. winding N is reversed and acts against the series winding S. When the tension rope c is unu'oiind and drives tlie armature A iii the opposite direction, viz; in the saine direction as the rotating field frame, the current de velopcd by armature c of the dyiiniiio acts t0 strengthen the current in the shunt. field winding N, thereby reducing llic relativo speed of the motor parts.

(')livionsly the auxiliary dynamo-electric machine may operato as u generator or ns n iiioloi with proper ell'eift, provided that it is driven hy the :iinnltnrior the field frame of the main motor A or even hy n separate iimtor.

l. ln un electric cable-wily isyslein, tlie lll) combination of an endless traveling cable, a straining rope to maintain a substantially uniform tension on said cable, an electric motor for operating the cable and straining rope, and a compensating dynamo electric machine in circuit with said motor operating .concurrently with the actuating of the straining rope.

2. In an electric cable-way s stem, the combination of an endless trave ing cable, a straining rope to maintain a substantiall uniform tension on said cable, an electric motor for operating the cable and straining rope, and a compensating generator driven bg' the straining rope operating element of t e motor, and energizing a compensating winding in the motor circuit.

3. In an electric cable-way system, the

combination of an endless traveling cable a. straining rope to maintain a substantiaily uniform tension on said cable, au electric motor having independently rotatable field and amature elements for actuating the traveling cable and the straining rope, and a generator driven by the motor element operating the straining rope and energizing a compensating winding m the motor circult.

Dated this the 28th day of March 1908.

In witness whereof I have hereunto set 30 my hand in the presence of two witnesses.

OTTO ADAM.

Witnesses:

JEAN GRUND, CARL Gnomi. 

